Write Control Method, Structured Document Management Apparatus, Structured Document Edit Apparatus, and Program Product

1. A computer implemented write control method of exclusively controlling write requests from a plurality of user terminals to an identical structured document, wherein the identical structured document includes a plurality of elements each containing document content, the method comprising: setting a field information that indicates a monitor field in units of the elements within the identical structured document; storing the identical structure document in a storage device; reading out the identical structured document from the storage device in response to read-out requests from the user terminals, and outputting the document thereto; receiving a write request from the user terminals, the write request including a difference document and different field information that indicates a field in the identical structured document; determining if the write request is directed to the document content under monitoring by referral to the monitor field; denying the write request to prevent overwriting of the document content, if the document content has been rewritten by a previous write request; and writing the difference document extracted from the write request into the field indicated by the different field information of the identical structured document stored in the storage device, if the write request has not been denied.

2. The method according to claim 1 , wherein said monitor field is set in a unit that exceeds sub-elements, the sub-elements having dependency relations with each other within the identical structured document.

3. The method according to claim 1 , further comprising: storing a table in which a correspondence between an identity of a document structure of the structured document and a name of the element to which said monitor field is set is recorded.

4. The method according to claim 1 , further comprising: using a time as a version number at which the document content in the monitor field was rewritten last; and checking the version number to which said one write request is directed.

5. A structured document management apparatus comprising: a storage configured to store a structured document which includes a plurality of elements each containing document content; a setting device configured to set a field information that indicates a monitor field in units of the elements within the structured document; a reader device configured to read out the structured document from the storage device in response to read-out requests from user terminals, and to output the document thereto; a receiver device configured to receive a write request from the user terminals, the write request including a difference document and different field information that indicates a field in the structured document; a determining device configured to determine if the write request is directed to the document content under monitoring by referral to the monitor field; and a request handler device configured to deny the write request to prevent overwriting of the document content, if the document content has been rewritten by a previous write request; and a writer device configured to write the difference document extracted from the write request into the field indicated by the different field information of the structured document stored in the storage device, if the write request has not been denied.

6. The apparatus according to claim 5 , wherein said monitor field is set in a unit that exceeds sub-elements, the sub-elements having dependency relations with each other within the structured document.

7. The apparatus according to claim 5 , wherein the storage stores a table in which a correspondence between an identity of a document structure of the structured document and a name of the element to which said monitor field is set is recorded.

8. The apparatus according to claim 5 , wherein the handling device uses a time at which the document content in the monitor field was rewritten last as a version number, and checks the version number to which said one write request is directed.

9. A computer program product embodied on a computer readable medium for exclusively controlling write requests from a plurality of user terminals to an identical structured document, wherein the identical structured document includes a plurality of elements each containing document content, comprising: a code segment that sets a field information that indicates a monitor field in units of the elements within the identical structured document; a code segment that instructs a storage device to store the identical structured document; a code segment that reads out the identical structured document from the storage device in response to read-out requests from the user terminals, and outputs the document thereto; a code segment that receives a write request from the user terminals, the write request including a difference document and different field information that indicates a field in the identical structured document; a code segment that determines if the write request is directed to the document content under monitoring by referral to the monitor field; a code segment that denies the write request to prevent overwriting of the document content, if the document content has been rewritten by a previous write request; and a code segment that writes the difference document extracted from the write request into the field indicated by the different field information of the identical structured document stored in the storage device, if the write request has not been denied.